WebBrowser控件不工作

我正在用C#开发一个Windows Phone 7应用程序。

我正在尝试使用Facebook登录页面进行登录。

这是我的cs来源：

namespace FacebookLogin
{
    public partial class MainPage : PhoneApplicationPage
    {
        private const string appId = "xxx";
        private const string apiKey = "xxx"; //insert your apps key here... see developers.facebook.com/setup/
        private readonly string[] extendedPermissions = new[] { "user_about_me" };
        private bool loggedIn = false;
        private FacebookClient fbClient;
        PhoneApplicationService appService = PhoneApplicationService.Current;
        // Constructor
        public MainPage()
        {
            InitializeComponent();
            fbClient = new FacebookClient();
            FacebookLoginBrowser.Loaded += new RoutedEventHandler(FacebookLoginBrowser_Loaded);
            //FacebookLoginBrowser.Navigated +=new EventHandler<System.Windows.Navigation.NavigationEventArgs>(FacebookLoginBrowser_Navigated);
        }
        private void FacebookLoginBrowser_Loaded(object sender, RoutedEventArgs e)
        {
            if (!loggedIn)
            {
                LoginToFacebook();
            }
        }
        private void FacebookLoginBrowser_Navigated(object sender, System.Windows.Navigation.NavigationEventArgs e)
        {
            FacebookOAuthResult oauthResult;
            if (FacebookOAuthResult.TryParse(e.Uri, out oauthResult))
            {
                if (oauthResult.IsSuccess)
                {
                    fbClient = new FacebookClient(oauthResult.AccessToken);
                    loggedIn = true;
                    loginSucceeded();
                }
                else
                {
                    MessageBox.Show(oauthResult.ErrorDescription);
                }
            }
        }
        private void LoginToFacebook()
        {
            TitlePanel.Visibility = Visibility.Visible;
            FacebookLoginBrowser.Visibility = Visibility.Visible;
            InfoPanel.Visibility = Visibility.Collapsed;
            var loginParameters = new Dictionary<string, object>
                                      {
                                          { "response_type", "token" }
                                          // { "display", "touch" } // by default for wp7 builds only (in Facebook.dll), display is set to touch.
                                      };
            var navigateUrl = FacebookOAuthClient.GetLoginUrl(appId, null, extendedPermissions, loginParameters);
            FacebookLoginBrowser.Navigate(navigateUrl);
        }
        // At this point we have an access token so we can get information from facebook
        private void loginSucceeded()
        {
            TitlePanel.Visibility = Visibility.Visible;
            FacebookLoginBrowser.Visibility = Visibility.Collapsed;
            InfoPanel.Visibility = Visibility.Visible;
            fbClient.GetCompleted +=
                (o, e) =>
                {
                    if (e.Error == null)
                    {
                        var result = (IDictionary<string, object>)e.GetResultData();
                        Dispatcher.BeginInvoke(() => MyData.ItemsSource = result);
                    }
                    else
                    {
                        MessageBox.Show(e.Error.Message);
                    }
                };
            fbClient.GetAsync("/me");
        }
        protected override void OnNavigatedFrom(System.Windows.Navigation.NavigationEventArgs args)
        {
            appService.State["fbClient"] = fbClient;
            base.OnNavigatedFrom(args);
        }
        protected override void OnNavigatedTo(System.Windows.Navigation.NavigationEventArgs args)
        {
            base.OnNavigatedTo(args);
        }
    }
}

这是我的XAML代码：

<phone:PhoneApplicationPage 
    x:Class="FacebookLogin.MainPage"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:phone="clr-namespace:Microsoft.Phone.Controls;assembly=Microsoft.Phone"
    xmlns:shell="clr-namespace:Microsoft.Phone.Shell;assembly=Microsoft.Phone"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d" d:DesignWidth="480" d:DesignHeight="768"
    FontFamily="{StaticResource PhoneFontFamilyNormal}"
    FontSize="{StaticResource PhoneFontSizeNormal}"
    Foreground="{StaticResource PhoneForegroundBrush}"
    SupportedOrientations="Portrait" Orientation="Portrait"
    shell:SystemTray.IsVisible="True">
    <Grid x:Name="LayoutRoot" Background="Transparent">
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="*"/>
        </Grid.RowDefinitions>
        <StackPanel x:Name="TitlePanel" Grid.Row="0" Margin="12,17,0,28" Visibility="Collapsed">
            <TextBlock x:Name="ApplicationTitle" Text="MI APLICACIÓN" Style="{StaticResource PhoneTextNormalStyle}"/>
            <TextBlock x:Name="PageTitle" Text="nombre de la página" Margin="9,-7,0,0" Style="{StaticResource PhoneTextTitle1Style}"/>
        </StackPanel>
        <Grid x:Name="ContentPanel" Grid.Row="1" Margin="12,0,12,0">
            <phone:WebBrowser HorizontalAlignment="Left" Name="FacebookLoginBrowser" Height="607" VerticalAlignment="Top" Width="450" />
            <Grid x:Name="InfoPanel" Grid.Row="1">
                <ListBox x:Name="MyData" Height="657" HorizontalAlignment="Stretch" VerticalAlignment="Top">
                    <ListBox.ItemTemplate>
                        <DataTemplate>
                            <Grid HorizontalAlignment="Stretch" MinWidth="500">
                                <Grid.ColumnDefinitions>
                                    <ColumnDefinition/>
                                    <ColumnDefinition/>
                                </Grid.ColumnDefinitions>
                                <TextBlock Grid.Column="0" Text="{Binding Key}"/>
                                <TextBlock Grid.Column="1" Text="{Binding Value}" TextWrapping="Wrap"/>
                            </Grid>
                        </DataTemplate>
                    </ListBox.ItemTemplate>
                </ListBox>
            </Grid>
        </Grid>
    </Grid>
    <!--<phone:PhoneApplicationPage.ApplicationBar>
        <shell:ApplicationBar IsVisible="True" IsMenuEnabled="True">
            <shell:ApplicationBarIconButton IconUri="/Images/appbar_button1.png" Text="Botón 1"/>
            <shell:ApplicationBarIconButton IconUri="/Images/appbar_button2.png" Text="Botón 2"/>
            <shell:ApplicationBar.MenuItems>
                <shell:ApplicationBarMenuItem Text="Elemento de menú 1"/>
                <shell:ApplicationBarMenuItem Text="Elemento de menú 2"/>
            </shell:ApplicationBar.MenuItems>
        </shell:ApplicationBar>
    </phone:PhoneApplicationPage.ApplicationBar>-->
</phone:PhoneApplicationPage>

错误在哪里？从未到达FacebookLoginBrowser_Navigated。